Clinic visits in late-life depression trials: effects on signal detection and therapeutic outcome

Blinding and expectancy confounds in psychedelic randomized controlled trials

Introduction: There is increasing interest in the potential for psychedelic drugs such as psilocybin, LSD and ketamine to treat several mental health disorders, with a growing number of randomized controlled trials (RCTs) being conducted to investigate the therapeutic effectiveness of psychedelics.Areas covered: We review previous literature on expectancy effects and blinding in the context of psychedelic RCTs - literature which strongly suggest that psychedelic RCTs might be confounded by de-blinding and expectancy. We conduct systematic reviews of psychedelic RCTs using Medline, PsychInfo and EMBASE (Jan 1990 - Nov 2020) and show that currently reported psychedelic RCTs have generally not reported pre-trial expectancy, nor the success of blinding procedures.Expert opinion: While psychedelic RCTs have generally shown promising results, with large effect sizes reported, we argue that treatment effect sizes in psychedelic RCTs are likely over-estimated due to de-blinding of participants and high levels of response expectancy. We suggest that psychedelic RCTs should routinely measure de-blinding and expectancy. Careful attention should be paid to clinical trial design and the instructions given to participants to allow these confounds to be reduced, estimated and removed from effect size estimates. We urge caution in interpreting effect size estimates from extant psychedelic RCTs.

Providing open-label placebos remotely-A randomized controlled trial in allergic rhinitis

Background

Placebos can reduce physical symptoms even when provided with full honesty and disclosure. Yet, the precise mechanisms underlying the effects of “open-label placebos” (OLPs) have remained subject of debate. Furthermore, it is unclear whether OLPs are similarly effective when provided remotely, as is sometimes required e.g. in the current COVID-19 pandemic.

Methods

In a randomized-controlled trial, we examined the effects of OLP plus treatment as usual (TAU) compared to TAU alone on symptom reduction in people with allergic rhinitis (N = 54) over the course of two weeks. Due to the COVID-19 pandemic, OLP was provided remotely (i.e. sent via postal service). To investigate the potential influence of the clinical encounter on the effects of OLP, we manipulated the perception of the virtual clinical encounter, both with respect to verbal and nonverbal factors (augmented vs. limited encounter).

Results

The results of the manipulation check confirmed that the augmented clinical encounter was evaluated more positively than the limited encounter, in terms of perceived warmth of the provider. Participants from all treatment groups showed significant symptom reduction from baseline to two weeks later, but OLP had no incremental effect over TAU. Participants benefitted more from OLP when they did not take any other medication against allergic symptoms than when taking medication on demand. When controlling for baseline symptoms, a significant treatment by encounter interaction was found, pointing to greater symptom improvement in the OLP group when the encounter was augmented, whereas the control group improved more when the encounter was limited.

Discussion

The study demonstrates that providing OLP and enhancing the encounter remotely is possible, but their effectiveness might be lower in comparison to previous studies relying on physical patient-provider interaction. The study raises questions for future research about the potential and challenges of remote placebo studies and virtual clinical encounters. The study has been registered as a clinical trial at ISRCTN (record number: 39018).

Placebo prevents rumination: An experimental study

BACKGROUND

Rumination is a risk factor for the development and maintenance of depressive symptoms and represents an important target for the treatment of depression. In the present study, we aimed to examine whether rumination can be reduced when participants are led to believe that they would receive medication that would prevent them from ruminating.

METHODS

In healthy participants (N= 91), an initial dysphoric state was induced via mood-suggestive music and autobiographic recall. Subsequently, participants were randomly assigned to one of two groups: an experimental group that received a deceptive active placebo via intranasal application accompanied by expectancy-enhancing instructions vs. a no-treatment control group. Then, rumination was induced via a rumination-activating task. The primary outcome was current rumination; experienced sadness was considered a secondary outcome.

RESULTS

Consistent with the hypothesis, participants receiving the placebo reported a significantly lower increase in current rumination (d= 0.57) and a higher decrease in sadness (d= 0.69) after the experimental induction than the control group.

LIMITATIONS

The external validity of this study might be limited due to the highly educated student sample.

CONCLUSIONS

The results suggest that rumination processes as well as experienced sadness can be positively influenced by placebo treatment. To evaluate its clinical potential, placebo-induced expectancy effects in rumination research should be further examined, particularly with clinically depressed patients. Also, the results imply that clinicians might consider the effects of expectations on patients' rumination tendencies, for example by explicitly addressing patients' expectations about rumination, mood, and the treatment in general.

[The role of placebo and nocebo mechanisms in depressive diseases and their treatment]

BACKGROUND

There is substantial evidence that placebo and nocebo effects occur during treatment with antidepressants. A better understanding of the underlying mechanisms of these effects is necessary to optimize the outcome of treatment and to make clinical studies more sensitive.

METHODS

Placebo and nocebo mechanisms were analyzed based on empirical studies and the results are summarized in a narrative review.

RESULTS

Clinical studies and also experimental mechanism-oriented studies underline the effects of placebo and nocebo mechanisms in the treatment with antidepressants.

CONCLUSION

The success of treatment in the use of antidepressants can be increased and the probability of side effects can be reduced by the effective use of placebo mechanisms and reduction of nocebo effects. The results emphasize the influence of clinician-patient interactions, the role of the treatment context and previous experiences with other treatments of the patient. Simultaneously, the results of this research field stimulate a new understanding of mental disorders, in particular depression and also provide points of reference for optimization of psychotherapeutic treatment.

Placebo Response in Chronic Idiopathic Constipation: A Systematic Review and Meta-Analysis

OBJECTIVES

Chronic idiopathic constipation (CIC), like other functional gastrointestinal disorders, has been associated with a high placebo response rate. However, the placebo response in randomized controlled trials has not been described.

METHODS

We conducted a search of the medical literature following the protocol outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement using MEDLINE, EMBASE and EMBASE Classic, Web of Science, and the Cochrane Central Register of Controlled Trials for all drugs used for the treatment of CIC. Two independent reviewers performed eligibility assessment and data extraction. The mean response rate was examined for the following 2 responder endpoints: (i) greater than or equal to 3 complete spontaneous bowel movements (CSBMs)/wk (≥3 CSBMs/wk responders) and (ii) mean increase of ≥1 CSBM/wk compared with baseline (increase in ≥1 CSBM/wk responders).

RESULTS

A total of 23 placebo-controlled trials met our inclusion criteria and were included in this meta-analysis. The placebo response in CIC trials ranged from 4% to 44%. The magnitude of the placebo response was 13% (95% confidence interval 11%-16%) with the ≥3 CSBM/wk responder endpoint and 28% (95% confidence interval 21%-30%) with the increase of ≥1 in the CSBM responder endpoint. Higher baseline CSBM, older age, and trials with more male participants were significantly associated with a stronger placebo response for both the ≥3 CSBMs/wk endpoint and increase in the ≥1 CSBM/wk endpoint. Trial characteristics such as location (Europe vs Asia/United States) and laxative class (prokinetic vs secretagogue) revealed key differences in the placebo response for both endpoints. The placebo response was not significantly affected by the number of study visits, study duration, year of publication, number of drop outs, or likelihood of receiving active drug.

DISCUSSION

The placebo response in CIC trials ranges from 4% to 44% depending on the endpoint. Modifying factors of the placebo response include multiple subject and trial characteristics.

Not Just Nonspecific Factors: The Roles of Alliance and Expectancy in Treatment, and Their Neurobiological Underpinnings

Therapeutic factors such as alliance and expectancy have been found to greatly affect treatment outcome in both psychotherapy and psychopharmacotherapy. Often, these factors are referred to as nonspecific because of their common roles across treatment modalities. Here we argue that conceptualizing such factors as nonspecific is not accurate at best, misleading at worst and may undermine treatment outcome across various modalities. We argue that alliance and expectancy contain both a trait-like common factor component and a state-like specific effect, and that it is clinically, conceptually and methodologically critical to disentangle the two. In other words, both alliance and expectancy may also function as active ingredients of treatment, leading to better outcome. We review the literature regarding the neurobiological underpinnings of alliance and of the expectancy effect, and suggest how future studies on the neurobiological basis of these effects can shed further light on the potentially distinct mechanisms of the trait-like and state-like components of each therapeutic factor.

A Machine Learning Approach to Identifying Placebo Responders in Late-Life Depression Trials

OBJECTIVE

Despite efforts to identify characteristics associated with medication-placebo differences in antidepressant trials, few consistent findings have emerged to guide participant selection in drug development settings and differential therapeutics in clinical practice. Limitations in the methodologies used, particularly searching for a single moderator while treating all other variables as noise, may partially explain the failure to generate consistent results. The present study tested whether interactions between pretreatment patient characteristics, rather than a single-variable solution, may better predict who is most likely to benefit from placebo versus medication.

METHODS

Data were analyzed from 174 patients aged 75 years and older with unipolar depression who were randomly assigned to citalopram or placebo. Model-based recursive partitioning analysis was conducted to identify the most robust significant moderators of placebo versus citalopram response.

RESULTS

The greatest signal detection between medication and placebo in favor of medication was among patients with fewer years of education (≤12) who suffered from a longer duration of depression since their first episode (>3.47 years) (B = 2.53, t(32) = 3.01, p = 0.004). Compared with medication, placebo had the greatest response for those who were more educated (>12 years), to the point where placebo almost outperformed medication (B = -0.57, t(96) = -1.90, p = 0.06).

CONCLUSION

Machine learning approaches capable of evaluating the contributions of multiple predictor variables may be a promising methodology for identifying placebo versus medication responders. Duration of depression and education should be considered in the efforts to modulate placebo magnitude in drug development settings and in clinical practice.

Are placebo and drug-specific effects additive? Questioning basic assumptions of double-blinded randomized clinical trials and presenting novel study designs

Double-blinded randomized clinical trials (RCTs) assume that pharmacological interventions have drug-specific and unspecific components. Traditional RCTs postulate an additivity of these two components. In this review, we provide evidence from both clinical trials and experimental studies that questions this 'additive model'. Given that the evaluation of drug treatments in RCTs is based on the assumption of additivity, its violation has far-reaching consequences. Therefore, we discuss an interactive model that, in contrast to the additive model, considers interactions between placebo and drug-specific effects. Moreover, we discuss implications for future clinical trials and present novel study designs enabling researchers to consider the complex interplay of drug-specific and unspecific effects.

Psychiatrists' Attitudes Toward Non-Pharmacologic Factors Within the Context of Antidepressant Pharmacotherapy

OBJECTIVE

Recent meta-analyses of antidepressant clinical trials have suggested that up to 82 % of response can be attributed to non-medication-related factors. The present study examines psychiatrists' attitudes regarding non-pharmacologic factors within the context of antidepressant pharmacotherapy.

METHODS

A web-based, 20-question cross-sectional survey was distributed to 101 staff psychiatrists and 48 post-graduate trainees in psychiatry at an academic hospital in Boston, MA. Demographics, practice characteristics, beliefs about non-pharmacologic factors affecting prescribing practices, perceived response and remission rates, and opinions about the need for further investigations in the psychopharmacology process were assessed.

RESULTS

Overall completion rate was 53 %. The final sample included 79 responses. The medians for clinician-perceived response rates (54 %) and remission rates (33 %) were in agreement with published rates. The reported median of the what portion of clinical outcomes is believed to be due to placebo effects (26 %) was numerically lower than suggested by literature. The contribution of the active ingredients of medications was perceived to be significantly higher than the contribution of patient characteristics and clinician characteristics. A longer time since graduation from medical school was significantly associated with higher belief in the effect of the active ingredients of antidepressant medications and with less perceived importance of placebo effects.

CONCLUSION

These findings suggest a discrepancy between empirical evidence and psychiatrists' beliefs on the impact of placebo effects on clinical outcomes. Educating antidepressant prescribers about the evidence based on psychosocial mediators of placebo effects' contribution to outcome may represent a promising strategy for improving clinical outcomes.

Geriatric characteristics in randomised controlled trials on antidepressant drugs for older adults: a systematic review

OBJECTIVE

Meta-analyses of antidepressant drug treatment trials have found that increasing age is associated with a less favourable outcome. Because the prevalence of geriatric characteristics, like disability, medical co-morbidity, malnutrition, cognitive (dys)function and frailty increase with age and are associated with depression, these characteristics are likely to modify the treatment outcome of antidepressant drugs in late-life depression. This review examines how these five characteristics are taken into account in randomised controlled trials (RCTs) with antidepressant drugs for major depressive disorder in patients aged 60 years or above.

DESIGN

A systematic search in PubMED, PsychInfo and EMBASE, from the year 2000 onwards, yielded 27 RCTs, with a total of 6356 subjects with a median age of 71 years. Two reviewers independently assessed whether each characteristic was considered as inclusion or exclusion criterion, descriptive variable, stratification variable, co-variable, outcome measure, or in adverse effect monitoring.

RESULTS

Malnutrition and frailty were not taken into account in any study. Disability was used as an outcome measure in five studies. Two studies explicitly included a population with possibly serious medical co-morbidity. Cognitive status was the only condition taken into account as co-variable (n = 3) or stratifying variable (n = 1) and was used as outcome measure in seven studies.

CONCLUSIONS

We conclude that geriatric characteristics are rarely taken into account in RCTs on antidepressant drugs in late-life depression, and studies including the oldest adults are underrepresented. This warrants recruitment of the oldest adults and adjustment of treatment strategies in future studies. Copyright © 2016 John Wiley & Sons, Ltd.

Practising evidence-based medicine in an era of high placebo response: number needed to treat reconsidered

The number needed to treat (NNT) statistic was developed to facilitate the practice of evidence-based medicine. Placebo was assumed to be therapeutically inert when the NNT was originally conceived, but more recent data for conditions such as major depressive disorder (MDD) suggest that the placebo control condition can have considerable therapeutic effects. Complications arise because the NNT calculated from randomised controlled trials (RCTs) reflects a comparison between medication plus clinical management and placebo plus clinical management, whereas, in the clinical setting, physicians choose between prescribing open medication, observing a patient over time with a supportive approach, and doing nothing. Thus, NNTs derived from clinical trials are not directly relevant to clinical decision-making, because they are based on control conditions that do not exist in standard practice. Additional difficulties may arise when using NNTs to compare alternative treatments for MDD, such as medication and psychotherapy, since these comparisons require the control conditions upon which the respective NNTs are based to be similar.Whereas pill placebo conditions include intensive clinical management and elicit expectations of improvement, attention control conditions for psychotherapy research are less well developed. Often the effects of psychotherapy are gauged against a wait-list control condition, which has substantially fewer therapeutic components than a pill placebo control condition. To improve the clinical utility of NNTs for the treatment of MDD, we advocate effectiveness studies that include treatment conditions resembling actual clinical practice, rather than using placebo-controlled RCTs for this purpose. Until such studies are performed, the effect of bias in comparing NNTs across treatments can be controlled by ensuring that the RCT control conditions upon which the NNTs are based are comparable.

INFLUENCE OF STUDY DESIGN ON TREATMENT RESPONSE IN ANXIETY DISORDER CLINICAL TRIALS

OBJECTIVE

The influence of study design variables and publication year on response to medication and placebo was investigated in clinical trials for social anxiety disorder (SAD), generalized anxiety disorder (GAD), and panic disorder (PD).

METHOD

Hierarchical linear modeling determined whether publication year, treatment assignment (medication vs. placebo), study type (placebo-controlled or active comparator), study duration, and the number of study visits affected the mean change associated with medication and placebo.

RESULTS

In the 66 trials examined, the change associated with both medication and placebo increased over time (t = 4.23, df = 39, P < .001), but average drug-placebo differences decreased over time (t = -2.04, df = 46, P = .047). More severe baseline illness was associated with greater drug-placebo differences for serotonin norepinephrine reuptake inhibitors (SNRIs, t = 3.46, df = 106, P = .001) and selective serotonin reuptake inhibitors (SSRI, t = 10.37, df = 106, P < .001). Improvement with medication was significantly greater in active-comparator studies compared to placebo-controlled trials (t = 3.41, df = 39, P = .002). A greater number of study visits was associated with greater symptom improvement in PD trials relative to SAD (t = 2.83, df = 39, P = .008) and GAD (t = 2.16, df = 39, P = .037).

CONCLUSIONS

Placebo response is substantial in SAD, GAD, and PD trials, and its rise over time has been associated with diminished drug-placebo differences. Study design features that influence treatment response in anxiety disorder trials include patient expectancy, frequency of follow-up visits, and baseline illness severity.

Age and sex as moderators of the placebo response – an evaluation of systematic reviews and meta-analyses across medicine

Predictors of the placebo response (PR) in randomized controlled trials (RCT) have been searched for ever since RCT have become the standard for testing novel therapies and age and gender are routinely documented data in all trials irrespective of the drug tested, its indication, and the primary and secondary end points chosen. To evaluate whether age and gender have been found to be reliable predictors of the PR across medical subspecialties, we extracted 75 systematic reviews, meta-analyses, and meta-regressions performed in major medical areas (neurology, psychiatry, internal medicine) known for high PR rates. The literature database used contains approximately 2,500 papers on various aspects of the genuine PR. These ‘meta-analyses’ were screened for statistical predictors of the PR across multiple RCT, including age and gender, but also other patient-based and design-based predictors of higher PR rates. Retrieved papers were sorted for areas and disease categories. Only 15 of the 75 analyses noted an effect of younger age to be associated with higher PR, and this was predominantly in psychiatric conditions but not in depression, and internal medicine but not in gastroenterology. Female gender was associated with higher PR in only 3 analyses. Among the patient-based predictors, the most frequently noted factor was lower symptom severity at baseline, and among the design- based factors, it was a randomization ratio that selected more patients to drugs than to placebo, more frequent study visits, and more recent trials that were associated with higher PR rates. While younger age may contribute to the PR in some conditions, sex does not. There is currently no evidence that the PR is different in the elderly. PR are, however, markedly influenced by the symptom severity at baseline, and by the likelihood of receiving active treatment in placebo- controlled trials.

Should antidepressant medication be used in the elderly?

Late-life depression is a serious illness accompanied by medical morbidity, cognitive decline and risk of suicide. Antidepressant medications are a cornerstone of treatment for depressed elders. Although they are optimally provided in conjunction with psychotherapy, in many cases they are used alone. Recently, concern has developed over modern antidepressant medication, including concerns about their ultimate efficacy and particular risks that may be seen in older adult populations. Ultimately, antidepressant medications are effective for many individuals and continue to play an important role in treating depressed elders, although the potential risks must be weighed with the patient and their families. Current data do not support restriction of their use and untreated depression has serious negative health consequences. Patients need treatments with better efficacy and safety, including new pharmacological options and better access to and dissemination of nonpharmacological treatment.

A systematic review and meta-analysis of psychotherapy for late-life depression

OBJECTIVES

To determine the efficacy of psychotherapy in late-life depression and to determine the effect of the type of control group on the magnitude of psychotherapy effects.

DESIGN

A systematic review and meta-analysis of randomized controlled psychotherapy trials for late-life depression.

SETTING

Outpatient clinics or in subjects' home.

PARTICIPANTS

Subjects aged 55 years or older with acute-phase depressive disorder.

MEASUREMENTS

Change in depressive symptoms was measured with validated scales. Standardized mean differences (SMD) were calculated for each therapy-control contrast, as meta-analytic summaries for contrasts using a similar control, and for all contrasts combined.

RESULTS

The search identified 27 trials with 37 therapy-control contrasts and 2,245 subjects. Trials utilized five types of control groups (waitlist, treatment-as-usual, attention, supportive therapy, placebo). In the combined contrasts, psychotherapy was effective (SMD: 0.73; 95% confidence interval [CI]: 0.51, 0.95; z=6.42, p<0.00001). The SMD varied widely (from 0.05 to 1.36) and significantly (χ2=35.67, df=4, p<0.00001) between subgroups by type of control. In five trials that compared psychotherapy with supportive therapy, the SMD was 0.39 (95% CI: 0.16, 0.61; z=3.37, p<0.0007; I2=0%). The SMD was 0.11 within the waitlist controls and 1.10 within the supportive therapy subgroup.

CONCLUSIONS

Psychotherapy is effective for late-life depression, but the magnitude of the effect varies widely with the type of control group. Supportive therapy appears to best control for the nonspecific elements of psychotherapy and is associated with considerable change itself, but few trials have utilized it as a control.

Placebo response in antipsychotic clinical trials: a meta-analysis

IMPORTANCE

Because increasing placebo response rates decrease drug-placebo differences and increase the number of failed trials, it is imperative to determine what is causing this trend.

OBJECTIVES

To investigate the relationship between antipsychotic medication and placebo response by publication year, and to identify associated study design and implementation variables.

DATA SOURCES

MEDLINE, PsycINFO, and PubMed were searched to identify randomized clinical trials of antipsychotic medications published from 1960 to July 2013.

STUDY SELECTION

Included were randomized clinical trials lasting 4 to 24 weeks, contrasting antipsychotic medication with placebo or an active comparator, and enrolling patients 18 years of age or older with schizophrenia or schizoaffective disorder.

DATA EXTRACTION AND SYNTHESIS

Standardized mean change scores were calculated for each treatment arm, plotted against publication year, and tested with Spearman rank correlation coefficients. Hierarchical linear modeling identified factors associated with the standardized mean change across medication and placebo treatment arms.

MAIN OUTCOMES AND MEASURES

We hypothesized that the mean change in placebo-treated patients would significantly increase from 1960 to the present, that a greater change would be observed in active comparator vs placebo-controlled trials, and that more protocol visits would increase the symptom change observed.

RESULTS

In the 105 trials examined, the mean change observed in placebo arms increased significantly with year of publication (n=39, r=0.52, P=.001), while the mean change in effective dose medication arms decreased significantly (n=208, r=-0.26, P<.001). Significant interactions were found between assignment to effective dose medication and publication year (t260=-5.55, P<.001), baseline severity (t260=5.08, P<.001), and study duration (t260=-3.76, P<.001), indicating that the average drug-placebo difference significantly decreased over time, with decreasing baseline severity and with increasing study duration. Medication treatment in comparator studies was associated with significantly more improvement than medication treatment in placebo-controlled trials (t93=2.73, P=.008).

CONCLUSIONS AND RELEVANCE

The average treatment change associated with placebo treatment in antipsychotic trials increased since 1960, while the change associated with medication treatment decreased. Changes in randomized clinical trials leading to inflation of baseline scores, enrollment of less severely ill participants, and higher expectations of patients may all be responsible.